DE2001345C3 - Process for the production of conjugated diolefins or for the simultaneous production of conjugated diolefins and acrolein and / or methacrolein - Google Patents

Description

the metal elements molybdenum, ursmut and'Uthium or sodium belong to oxygen; η are not all present, the effects of the invention cannot be obtained. The fXlvsator a small amount of phosphorus, boron, u 1 1 silicon. Like. Contained as Mischkalalysator. The process for preparing the catalyst is ι, -n such an important factor that the effects according to A invention are limited, and the catalyst can easily by known techniques, for. B. the Oxyd- »Uschmethode, evaporation and drying method and the mixed precipitation method can be produced. The starting materials of each of the elements that make up Jv Jen's catalyst need not necessarily be jr. have _porro of oxides, but can be present in ρ mi of the metals themselves or in the form of metal compounds or acids or bases, provided that they can be converted into their corresponding metal oxides by calcination. Further, in the preparation of the catalyst, the individual elements may be mixed as they are, or compounds containing at least two of the components may be used as starting materials. The catalyst obtained in this manner is preferably calcined in air at a temperature of 350 to 750 ° C, preferably 450 to 45O ⁰ C, a few hours up to a multiple of 10 hours before use. The catalyst according to the invention obtained in this way is formed by complex catalytic oxides, but their exact structure has not yet been established; In the present context it was not determined whether it is a simple mixture of several oxides or whether the elements listed are directly or indirectly bound by oxygen in a different manner.

As typical methods for preparing the catalyst, the following are given. In one method molybdenum oxide and bismuth oxide are mixed _sori jfältig; then an aqueous solution in which lithium hydroxide has been dissolved is added to the oxide mixture, whereupon it is carefully kneaded. The resulting composition is calcined and then ground into a suitable shape, such as pellets or finely divided particles. In another method, an aqueous solution of bismuth nitrate is added with stirring to an aqueous solution of ammonium molybdate, after which an aqueous solution of lithium hydroxide is added. The mixture is then carefully The concentration of the starting olefin (monoolefin or olefin mixture) in the gas used, which is introduced into the reaction vessel, is preferably in the range from 1 to 25 percent by volume. On the other hand, the molar ratio of the starting olefin to the molecular oxygen is expediently in the range of 1: (0.1 to 5.0). The reaction temperature can be appropriately selected depending on the type of reaction and its conditions; in general, a temperature of from 300 to 650 ° C. is used, a range of from 350 to 600 ° C. being particularly preferred. The reaction pressure used can be in the range from a reduced pressure below atmospheric pressure to an over-atmospheric pressure of 20 kg / cm ² , a pressure in the range from atmospheric pressure to a pressure of 5 kg / cm ^{1 being} particularly preferred (based on 0 ° C and 1 atm.) in the range of 0.01 to 50 seconds., preferably 0.1 to 15 seconds, applied.

While oxygen itself can be used as molecular oxygen, of course, so is the use of air more practical. In addition, inert gases that do not affect the reaction, such as steam, as nitrogen, saturated hydrocarbons (e.g. methane Ethane, propane, butane, pentane and hexane), are introduced into the reaction system.

The reaction device to be used in carrying out the method according to the invention can be of any of the known types, e.g. B. a fluidized bed type, moving bed type and fixed bed type apparatus. However, the process according to the invention is particularly effective when it is carried out as a fixed bed reaction in which regulation of the reaction temperature is considered difficult due to the heat generated by the catalytic reaction. . . The reaction product can be obtained by conventional techniques, e.g. B. is liquefied by condensation or is collected with a solvent. _ _c .

The two modes of operation according to the invention, i.e. the above mentioned methods 1 and are now described separately below.

50 Process I (preparation of conjugated diolefins)

_becomes a monoolefic of

Forming or pulverizing. Of the Catalyst can also be used diluted with Verdunnungsm.tte η. Furthermore, the ICatalysuior _ if desired - can be applied to a carrier. As such diluents or carriers can non-reactive aluminum oxide silicon carbide, Titanium dioxide, zirconium oxide, Thoru-.mch.orid, B.msstein Silica gel, sellaite, metallic aluminum and graphite

be cited. Since the Verdünnungsm.ttd or the sponsor has no significant influence on the

Exercise of the catalyst, the amount in that they are used in a suitable way.

the

\ kr _; tc ung
¹ ^

from soamylenic (i.e., 2-methylbutene-2) processes. 912 795 becomes a

y £ \
and pensions ^ to
s, ch de then
only au Biu.η

_{n v0 “Butene} to Butadiene ™ MafS. _n , _{but also} refer to ^G _s ^ _zi n examples _{for the}

Isoprene based on the example of Umin Butadiene (example 1 of the other

led patent) the temperature of the catalyst • atorschicht by 50 ⁰ C due to heat generation at a reaction temperature of 430 "C. This fact can be seen that in the oxidation reaction of isoamylenes to isoprene using a molybdenum / bismuth catalyst a a considerable increase in temperature would occur inside the catalyst layer; not only would it be very difficult to regulate the reaction temperature, but isoprene yield and selectivity would also be reduced. The technical value of this catalyst is therefore doubtful. In fact (as in the table below I), if the temperature inside the catalyst layer is increased considerably (as much as 70 ^° C.) in the conversion reaction of 2-methylbutene-2 into isoprene, regulation of the reaction temperature is very difficult. Furthermore, the isoprene yield per pass of the starting material is only 29.8% Furthermore, in addition to the disadvantages listed above The reproducibility of the molybdenum / bismuth catalyst is low, since very small differences in its position conditions affect both the controllability of the reaction temperature and the reaction results. It can thus be seen that the molybdenum / bismuth catalyst has many disadvantages in its application in the art. On the other hand, a binary molybdenum / lithium (or sodium) catalyst as a catalyst for obtaining butadiene by the oxidation of butene is described in U.S. Patent 3,119,111, in which an example is given. According to Example 1 of the USA. Patent cited above, the yield of butadiene is 17.7% and its selectivity 21% when the M0I5 barium / lithium catalyst is used at the elevated reaction temperature of 600.degree. C. In Example 2, the case is used described, in which butene is recycled.In any case, it is to be assumed that the molybdenum / lithium catalyst is a catalyst with very low activity.

In fact, the activity of this catalyst is extremely low. Such as B. in the following Table I indicated is in the conversion reaction of 2-methylbutene-2 to isoprene with this Catalyst practically no reactivity to be found.

In contrast, in method I using the catalyst according to the invention, e.g. B. the ternary molybdenum / bismuth / lithium catalyst, yield and selectivity of the conversion of 2-methylbutene-2 to isoprene 42.8% and 73.5%, which are surprisingly good values. Ferr.r was the temperature increase of only 21 KatalysatorschicM ^c C, which is less than one third the value of the molybdenum / bismuth catalyst. This largely avoids the chemical reaction and makes it possible to reduce the loss of the starting material to a high degree.

For comparison, the conversion reactions of 2-methylbutene-2 into Isoprene compiled by oxidation.

Tabel

catalyst
(Atomic ratio)

difference between the reaction stem Reaction temperature and the temperature maximum tem temperature in the Catalyst layer CC) ( ³ C) 440 65 450 70 487 2 500 -r- 0 441 18th 451 21

Implementation of

2-methyl

butene-2

Isoprene

Bulge

selectivity

Mon: Bi (1: 1)

Mon: Bi (1: 1)

Mo: Li (1: 1)

Mo: Li (1: 0.1)

Mo: Bi: Li (1: 1: 0, l)
Mo: Bi: Li (1: 1: 0.1)

49.6

58.9

8.5

- 0

51.4
58.2

29.2

29.8

4.4

37.1
42.8

58.8
50.6
51.2

72.2
73.5

Thus, from Table I above, it can be seen that the selectivity to conjugated diolefins can be increased according to the procedure of Process I, this by reducing the formation of carbon monoxide and carbon dioxide attributable to the combustion of starting material and the formation of unsaturated aldehydes as a result partial oxidation is achieved. Further, the heat generation in the catalyst layer such side reactions attributable due animal inhibition is made not only the temperature of the catalyst layer uniformly, to allow not only an easy control of the reaction temperature, but also prevent decomposition of the catalyst zv. Since, according to method I, the generation of large amounts of heat in the catalyst layer as a result of such secondary reactions can also be avoided, the concentration of monoolefin in the gas used can be increased above the value of known methods. In addition, according to method I, the bulge per passage of the gas used can be increased. It can be seen from the above that the process I is not only a technically feasible process, but that the production costs can also be reduced, since the reaction device can be made smaller; this shows that the process is also very advantageous from an economic point of view,

Process I is as a process for preparing the corresponding conjugated diolefins from the Monoolefins with 4 to 6 carbon atoms are suitable. For example ν is 1,3-butadiene from butene-1 or (cis- and trans-) Bt! ten-2 and isoprene from isoamylenes, such as 3-methylbutene-1,2-methylbutene-1 and 2-methylbutene-2, (cis- and trans-) piperylene from pentene-1 or (cis- and trans-) pentene-2, 2,3-dimethylbutadiene from 2,3-dimethylbutene-2 and 4-methylpenadiene-1.3 4-methylpentene-1 obtained.

Procedure II

(simultaneous production of unsaturated aldehydes and conjugated diolefins)

In process II, a mixture of (a) propylene and / or isobutene and (b) a monoolefin is used, the molecule of which has a linear chain of 4 to 6 carbon atoms. Process II makes it possible to obtain an economically viable yield under stable conditions To achieve reaction conditions when applied to the following cases:

Simultaneous production of acrolein and 1,3-butadiene from a mixture of propylene and n-butene;

simultaneous production of methacrolein and 1,3-butadiene from a mixture of isobutene and n-butene;

simultaneous production of acrolein and isoprene

from a mixture of propylene and isoamylene; simultaneous production of methacrolein and

Isoprene from a mixture of isobutene and isoamylene.

Process II is particularly effective as a process for the simultaneous production of methacrolein and 1,3-butene from a mixture of isobutene and n-butene. Although the synthesis of methacrolein or 1,3-butadiene, in which isobutene or n-butene are independently subjected to a Kalalyian vapor phase oxidation reaction as described above, is known and its industrial production is also feasible, it should be mentioned that it is required as Use raw materials isobutene and n-butene with high purity. However, isobutene and n-butene are technically obtained either by separation from the so-called (! ,, - fraction (a mixture of n-butene, isobutene, η-butane, isobutane and butadiene) or by separation from the extracted cyi fraction, which after extraction of butadiene etc. from the crude remains: since the various constituents of these mixtures are very similar in their physical and chemical properties, it is neither easy to isolate isobutene and n-butene alone from these mixtures, nor is it easy to isolate As a result, isobutene and n-butene to be used as chemical materials become expensive. On the other hand, in recent years, with the development of the petrochemical industry, there has been an increase in the production of C ₄ fractions or extracted , after extraction of 1,3-butadiene from the former remaining C ₄ fractions took place, which as a by-product in the cracking of earth oil naphtha are produced. It is therefore imperative that an efficient way of using these fractions be found. Since method II enables the C ₄ fractions or the extracted C ₄ fractions to be used as starting material (since components other than butene contained in the C ₄ fractions and in the extracted C ₄ fractions, e.g. Butadiene, isobutane and η-butane, essentially not taking part in the reaction, they can only be regarded as diluents), the importance of this process is very great.

Furthermore, according to method II, only unsaturated aldehydes and conjugated diolefins are obtained in good yield educated. The formation of unsaturated acids is low, and the greater part is by-products either carbon monoxide or carbon dioxide. Furthermore, the unsaturated aldehydes and conjugated Diolefins differ greatly from one another in their physical and chemical properties, they will easily separated and cleaned. The separation and purification of the by-products can also be carried out easily

ίο be carried out.

Process II not only enables the simultaneous production of unsaturates with good yield Aldehydes and conjugated diolefins by adding in the presence of a specific catalyst different

t5 reactions with different courses - as described above - can be carried out, but also leads to an extraordinary technical effect, since it enables the direct use of the Q fractions and the extracted C ₄ fractions.

ao The binary molybdenum / bismuth catalyst of British patent specification 912 795 and the Japanese patent application 27 751/1968 is used as a catalyst for use in the separate production of unsaturated Aidehyde and conjugated diolefins have been suggested.

«5 However, if this catalyst even with the independent Reactions were used, the amount of undesirable by-products was large. Further stepped often difficulties in controlling the reaction temperature when used in a fixed bed reaction vessel because hot spots arose which caused the catalyst to decompose. Further Small differences in the manufacturing conditions of the catalyst affect both the controllability the reaction temperature and the result of the reaction, which makes it difficult to reproduce illustrated. Therefore, it is a poor catalyst for carrying out a technical Production of unsaturated aldehydes and conjugated diolefins. When the reaction (temperature

temperature 443 C) for the simultaneous production of methacrolein and butadiene from a mixture of isobutene and n-butene using the binary molybdenum / bismuth catalyst, the conversion of isobutene and n-butene was 38.1 ° and 9.6 °, respectively _n . and the yields of methacrolein and butadiene were 33.4 and 3.5 degrees. which are extraordinarily low values.

On the other hand, the binary molybdenum / lithium catalyst was disclosed in Kogyo Kagaku Zasshi, Vol. 67, No. 7

_so (1964), p. 1021, cited as a catalyst for the production of acrolein by oxidative conversion of propylene, but the yield of acrolein in this case was in the order of magnitude of traces, which results in a very low catalytic activity. Furthermore, practically no reactivity was found in this reaction to obtain methacrolein from isobutene using this catalyst. Furthermore, U.S. Patent 3,119,111 gives an example in which a binary

Molybdenum / lithium (or sodium) catalyst the production of butadiene by oxidation of butene is used, but were - as above stated - the results of the reaction are very unsatisfactory. If this binary molybdenum / Lithium catalyst in a reaction (temperature 449 C) for the simultaneous production of methacrolein and 1,3-butadiene was used from a mixture of isobutene and n-butene, the conversion

409 685/304

Settlements of isobutene and n-butene 15.2 and 4.6% and the yields of methacrolein and 1,3-butadiene 12.1 and 2.1%, respectively, which are very low values in both cases; practically no reactivity results from this emerged.

In contrast, when method II using rics catalyst according to the invention, e.g. B. a trinary molybdenum / bismuth / lithium catalyst was carried out, the conversions of isobutene and η-butene in the same reaction (temperature 442 ⁰ C), as described above, were 70.7 and 46.7% and the Yields of methacrolein and butadiene 59.9 and 44.7%, respectively; these are completely surprising results. Furthermore, no hot spots (which are always a problem with highly active catalysts) occurred during the reaction and very easy regulation of the temperature was achieved. There were also no side reactions.

The monoolefins used in Process II are those having 4 to 6 carbon atoms. Examples of this Monoolefins are n-butenes (i.e. n-butene-1, n-cis- and n-trans-butene-2, etc.), isoamylenes (i.e. 2-methylbutene-2, 2-methylbutene-1, 3-methylbutene-1 etc.), pentene-1, cis-pentene-2 or trans-pentene-2, 2,3-dimethylbutene-2, 4-methylpentene-1 or mixtures thereof. Propylene and isobutylene can also be used separately the monoolefins, or they can be mixed with, depending on the desired goal the monoolefins are mixed.

The concentration of the mixture of propylene (or isobutene) and monoolefin in the feed gas to be introduced into the reaction vessel should preferably be in Range from 1 to 25 percent by volume. On the other hand, the molar ratio of the mixture is Propylene (or isobutene) and monoolefin to mol-

Cular oxygen suitably in the range of 1: (0.1 to 5.0). The ratio of propylene (or Isobutene) and monoolefin in the mixture is not a factor detr any particular influence on the reaction exercises. Hence, the desired goal can be achieved with totally

Satisfactory results can be achieved even if the ratio of propylene (or isobutene) is too Monoolefin in a suitable manner (with the amount of one being greater than that of the other or vice versa) in Depending on the availability of the output

ao materials or the ratio in which the desired products are required, etc.

The invention is explained in more detail below by means of examples. The conversion, yield and selectivity rates, those given in the examples and in Table I above are denoted by calculated using the following equations:

Monoolefin conversion (%) = Monoolefin used (mol) - unreacted Monoolefin (mole)

Monoolefin used (mol)

, ".. unimplemented

Propylene or isobutene conversion (%) = -

Deployed

Propylene or isobutene used (mol) - unreacted propylene or isobutene (mol)

Propylene or isobutene used (mol)

100

Yield of conjugated olefin (/ _o ) = conjugated diolefin formed (mol)

100

Yield of unsaturated aldehydes (/ _o ) = - ^{rtu 6} Ein

Yield of (CO + CO ₂ ) (%) =

..., "^ A selectivity (%) =

Unsaturated aldehydes formed (mol) Propylene or isobutene used (mol) (CO + - CO ₂ ) formed (mol)
Monoolefin used (mol)

Yield conversion 100

100

100

Example 1 Preparation of a Mo / Bi / Li (or Na) / O catalyst

202 g of molybdenum trioxide and 236 g of bismuth oxide are carefully mixed, after which an aqueous solution of 5.9 g of lithium hydroxide (LiOH · H ₂ O) in 50 ml of water is added and mixed carefully. Then in air for 2 hours at 500 ⁰ C for aclciniert and then comminuted. A small amount of graphite is added to the crushed product and mixed thoroughly, after which tablets 5 mm in diameter and 5 mm in length are formed with a tablet machine. The tablets formed are then calcined in air for 16 hours at 550 ^° C. to obtain the catalyst. The atomic ratio of the metal elements in the thus obtained catalyst (A-2) is Mo: Bi: Li = 1: 1: 0.1. Catalysts (AI, AJ, A-4, A-5 and A-6) with the compositions given in Tables II to V are prepared in the same way. Molybdenum / bismuth / sodium / oxygen catalysts (A-7 and A-8), as shown in Tables II to V, are also proposed using sodium hydroxide instead

Lithium hydroxide produced.

60

Example 2

Manufacture of a molybdenum / bismuth / oxygen catalyst

202 g of molybdenum trioxide, 326 g of bismuth oxide and 50 ml of water are carefully mixed. Nad 2-hour calcination in air of this mixture be 65 500 ⁰ C, the calcined product is crushed. Since: the comminuted product is treated as in Example 1 and processed into a catalyst in tablet form. The atomic ratio of the metal elements of this catalyst

12th

sators (B-2) is Mo: Bi = 1: 1. There are catalysts (B-I and B-3) with the compositions given in Table II were prepared in the same way.

Example 3

Manufacture of a molybdenum / lithium (or sodium) / oxygen catalyst

16.8 g of lithium hydroxide (LiOH · H ₂ O) are dissolved in 50 ml of water. While this aqueous solution is being heated, 233 g of molybdenum trioxide are slowly added with stirring. The solution obtained in this way is dried by evaporation with careful stirring. The dried product is then treated as in Example 1 and processed into a catalyst in tablet form. The atomic ratio of the metal elements in this catalyst (C-2) is Mo: Li = 1: 0.1.

A catalyst (C-I) of the type shown in Table II specified composition prepared as described above, with the exception that a Calcination temperature of 450 "C and a CaI-cinierungs duration of 16 hours is used.

A molybdenum / sodium / oxygen catalyst (C-3) of the composition given in Table II is also used made using sodium hydroxide instead of lithium hydroxide.

Example 4

The various catalysts described above are in amounts of 60 ml each in a stainless steel reaction tube with an inner diameter of 25 mm and a length of 600 mm given, after which the oxidation reaction of 2-methylbutene-2 to isoprene by heating with a molten metal bath is carried out.

The molar ratio of 2-methylbutene-2 to oxygen to nitrogen to steam in the starting gas used is 1: 1: 11.5: 11.5 in all cases, and the apparent duration of contact is 3 seconds.

The results obtained are given in Table II: -. The symbol AT (shown in the table represents the difference between the temperature of the metal bath (reaction temperature) and the maximum temperature of the temperature distribution inside the catalyst layer, which has increased as a result of the exothermic reaction. The / ΙΓ value is therefore smaller by sc | The smaller or flatter the temperature distribution in the catalyst layer, which indicates that the regulation of the reaction temperature has been simplified to this extent.

Table II

(No.) Catalyst
(Atomic ratio)

temperature ΛΤ of the metal baths \ 'Reaction ( ¹ C) temperature) 15th ( ⁰ C) 8th 446 10 414 14th 425 18th 434 21 441 23 451 26th 459 7th 445 14th 411 15th 436 19th 446 9 455 23 416 28 443 13th 451 28 421 30th 441 U 450 19th 410 26th 420 30th 429 20th 444 26th 414 30th 421 32 429 438

Sales of

2-methyl

butene-2

Isoprene

yield

Selectivity (X)

CO + CO,

yield

r / o)

selectivity

(Example according to the invention)
Mo-Bi-Li (or Na) -O catalyst

(A-I) Mo: Bi-I i = 1: 0.5: 0.1

(A-2) Mo: Bi: Li == 1: 1: 0.1

(A-3) Mo: Bi: Li = I: 2: 0.1

(A-4) Mo: Bi: Li = 1: 1: 0.2

(A-5) Mo: Bi: Li = 1: 1: 0.07 <

(A-6) Mo: Bi: Li = 1: 1: 0.05

(A-7) Mo: Bi: Na- = 1: 1: 0.143

(A-8) Mo: Bi: Na = 1: 1: 0.1

34.2

24.9
35.6
45.3
51.4
58.2
58.4

56.2

26.5
43.9
48.8
54.4

32.8
57.3
61.0

35.8
50.1
54.4

? 9.7
39.9
50.6
54.1

41.3
47.7
51.2
52.5

22.4

20.9
26.6
32.9
37.1
42.8
39.4

34.8

20.3
31.6
34.6
35.2

25.1
37.6
37.8

26.7
34.4
35.8

21.9
27.0
32.1
34.0

28.9
31.5
34.5
35.4

65.5

83.9 74.7 72.4 72.2 73.5 67.5

62.0

76.6 71.9 70.9 64.7

76.5 65.6 61.9

74.5 68.7 f-5.8

73.8 67.7 63.4 62.8

70.0 66.1 67.4 67.4

2.3

2.7 3.8 4.7 5.5 6.2 6.6

7.0

2.2 4.3 5.1 5.7

2.7 5.4 5.6

3.6 5.8 6.3

3.1 4.8 6.1 7.1

5.0 5.8 6.6

/, 0

6.7

10.8 10.7 10.4 10.7 10.6

12.4

8.6

9.8

10.5

10.5

8.2 9.4 9.2

10.1 11.6 11.6

10.4 12.0 12.0 13.1

12.1 12.2 12.9 13.3

(No.) Catalyst
(Atomic ratio)

(Comparison)
Mo-Bi-O catalyst

(BI) Mo: Bi = 1: 0.5
(B-2) Mo: Bi = 1: 1.
(B-3) Mo: Bi = 1: 2.

(Comparison)

Mo-Li (or Na) -O-KaIaIy-

(C-I) Mo: Li = 1: 1

(C-2) Mo: Li - 1: 0.1
(C-3) Mo: Na = 1 ·· 1

Temperature of the metal bath

(Reaction temperature) ^{(0 C)}

444

413 432 440 450

440

450 487

500 500

- Sales of Isoprene selectivity CO J CO, AT 2-methyl- (%) butcn-2 yield 56.1 yield Slcktivit,
/ o / \ ( ⁰ C) (%) (%) 63.5 (Λ) I / o) 29 38.5 21.6 62.0 ]
4.6 11.9 46 32.9 20.8 58.8 6.2 18.8 SQ 45.7 28.4 50.6 8.3 18.2 65 49.6 29.2 50.0 10.1 20.4 70 58.9 29.8 36.4 12.6 21.4 67 49.0 24.5 51.2 10.5 21.3 0 4.5 1.6 43.1 0.4 5.2 2 8.5 4.4 0.5 5.9 0
1 .0
12.3 5.3 0.8 6.5

From Table II it can be seen that the difference between the reaction temperature and the temperature inside the catalyst layer in the method according to the invention compared to the comparative experiments is conspicuously low. It can also be seen that both the implementation of 2-methylbulcn-2 as also the yield of isoprene, the desired product, and its selectivity are extraordinary increase while the formation of carbon monoxide and carbon dioxide is decreased.

Example 5

The catalyst (A-2) used in Example 4 is used; the reactions are as in the example 4 carried out with the exception that the molar ratio of 2-methylbutene-2 to oxygen? U nitrogen to steam is varied. The results obtained are shown in Table III.

2-methylbulcn-2 to

Oxygen to nitrogen

/ 11 steam (M oil ratio)

1-1: 11.5: 11.5
1: 1: 4: 8 ....
1: 1: 4: 6 ....

Temperature of the metal bath (reaction temperature) ("O

451 467 470

AT

25 27

Table "HI

Sales of

2-methyl-

butene-2

58.2
52.7
53.0

Isoprene

yield

42.8
38.7
38.1

selectivity

\ / nl

73.5
73.3
71.9

yield

c;)

co j co.

6.2 5.9 3.8

selectivity

Elapsed
Time

20th

60

100

Temperature of AT Metal bath (Reaction temperature) CO <* O 22nd 450 22nd 451 20th 453 21 454

Sales of

2-methyl

butcn-2

(7o)

58.5 58.9 59.5 61.1

Table IV

Isoprene

yield

\ / at

.41.9
40.9
39.1
39.0

selectivity

70.6
69.4
65.1
63.8

CO f CO;

yield

7.0 6.7 6.6

5.8

Selectivity CO

Example 7

The conversion of butene-1 to 1,3-butadiene by oxidation is carried out as in Example 4 using the catalyst (A-2) used therein, with the exception that a reaction temperature of 432 ° C. and an apparent contact time of 3.0 Seconds is used, the molar ratio of the gas used, ie of butene-1 to oxygen to nitrogen to steam, being 1: 1: 4: 6. AT was 21 ° C., the conversion of butene-1 was 82.5%, and the yield and selectivity were 70.5 and 85.5%, respectively.

Example 8

By proceeding as in Example 4, reactions for the simultaneous production of methacrolein are carried out and butadiene by oxidation of a

mixture of isobutene and η-butene (mixture of n-butene-1, n-cis-butene-2 and n-trans-butene-2) carried out. The molar ratio of isobutene to n-butene to oxygen to nitrogen to steam is in all of them Cases 0.5: 0.5; 2: 8: 6, and it becomes an apparent one 3.6 seconds of contact time applied. The results obtained are shown in Table V. From Table V it can be seen that, according to the process according to the invention, methacrolein and 1,3-butadiene

ίο in extraordinarily good yield compared to the Settlement procedure and further both at lower. Temperatures and especially higher sales of isobutene and η-butene and also with particularly satisfactory higher selectivities.

t5 Furthermore, the formation of by-products such as Methacrylic acid, carbon monoxide and carbon dioxide, low.

Table V

ltor
Beilolickisse

(No.) Catalyst
Atomic ratio Temperature of
Metal construction
(Reaction
temperature, 'C) Umsa
Isobutene tz (%)
n-butene Yield (Se
Methacrolein ectivity) (%)
1,3-butadiene (Example according to the invention)
Mo-Bi-Li (or Na) -O-Kataly-
sator (A-2) Mo: Bi: Li = 1: 1: 0.1 .. 402
416
432
442 40.2
52.2
68.1
70.7 26.9
36.8
46.1
46.7 30.0 (76.2)
41.4 (79.3)
55.2 (81.0)
59.9 (84.7) 23.2 (86.3)
29.4 (81.1)
36.7 (79.7)
44.7 (95.9) (A-8) Mo: Bi: Na = 1: 1: 0.1 440 68.6 44.2 56.1 (81.8) 40.6 (91.8) (Comparison)
Mo-Bi-O catalyst (B-2) Mo: Bi = i: I 416
443
471
494 22.8
38.1
45.3
58.5 2.5
9.6
17.3
24.3 20.2 (88.7)
33.4 (87.8)
39.6 (37.5)
51.8 (88.7) 6.3 (30.7)
8.5 (88.5)
11.1 (64.0)
15.2 (62.7) (Comparison)
Mo-Li-OK analyzer 449
489 15.2
20.1 4.6
6.8 12.1 (79.7)
15.1 (75.3) 2.1 (45.6)
3.2 (47.0) (C-2) Mo: Li = 1: 0.1 ί

Example 9
Production of n-pentadiene-1,3 from n-pentene-1

The reaction for the preparation of n-pentadiene-1,3 by oxidation of n-pentene-1 was carried out in the same manner as in Example 4, with the exception that n-pentene-1 instead of 2-methylbutene-2 was used, where the ratio of n-pentene-1: O _s: N _a: H ₂ O in the feed gas to 1: 4 was maintained at a reaction temperature of 430 ° C: 1: 4. The catalyst used was the catalyst designated as A-2 in Example 4 (Table II), ie the catalyst with the composition Mo: Bi: Li = 1: 1: 0.1.

The conversion of n-pentene-1 was 53.6%, and the 55th

The selectivity and yield of n-penta-1,3-ene were 58.8% and 31.5%, respectively.

Comparative experiment

From Japanese patent application 7 881/67 the simultaneous production of methacrolein and Butadiene- (1,3) by catalytic oxidation of a mixture of isobutene and n-butene with oxygen in the presence of a catalyst consisting of vanadium pentoxide, molybdenum trioxide and bismuth trioxide known. To compare the method of Japanese Patent Application 7,881/67 with that of the invention a comparative test was carried out.

Catalysts A-2 and A-8 according to Example 1 were used as comparative catalysts according to the invention

(O

18th

Jl /

rooted. The catalyst, which is composed according to Japanese patent application metavanadate (NH ₄ VOj) vwused 1 881/67, was manufactured by ewRejK like the lysers. "

Catalyst A-2 prepared, but using 5.9 g instead. The results "num" j. Lithium hydroxide (LiOH-H ₂ O) 16.4 g of ammonium Table compared.

Catalyst (atomic ratio)

invention

^{i (} * Mo-Bi-Li = 1: 1: 0.1
*** Mo-Bi-Na = 1: 1: 0.1

Japanese patent application
7 881/67
Mo-Bi-V = 1: 1: 0.1

Reaction temperature

CC)

442
440

442

AT* CC)

sales

i-B

n-B

70.7
68.6

71.2

46.7
44.2

82.1

yield

TIMES

59.9
56.1

39.0

1,3-BD

44.7
40.6

50.2

selectivity
(%)

MAL I 1,3-BD

84.7
81.8

54.9

95.9
91.8

61.1

*) The SymboMT-rQ gives the deficit between the temperature of the Mcb.llb.de, ^^^ temperature of the temperature distribution within the catalyst layer, which ^ as a result of the Herrner, ^ U The smaller the value AT , the smaller the Temperature distribution within the katalysatorscnicni, and keep the reaction temperature under control.
* ·) And ** ·) Test (A-2) or (A-8) according to Table V.
iB = isobutene.
iB = n-butene.
MAL = methacrolein.
1,3-BD = 1,3-butadiene.

The table above shows the following:

(a) The value (35 to 37 ° C) in the method of the invention is extremely small, corresponding to about a third of the value ΔΤ (98 ° C) in the method using the catalyst according to Japanese patent application. This means that the control of the reaction temperature is extremely difficult in the method of the Japanese patent application. In fact, in this case, there was a rapid rise in temperature within the catalyst layer, which made control of the reaction temperature very difficult. The reason for this was that a combustion reaction occurred. In contrast, the process of the invention was very stable and the reaction temperature could be easily controlled.

(b) The yield of methacrolein is much higher in the process of the invention than in that Method of Japanese patent application.

(c) The yield of 1,3-butadiene is in the process of the Japanese patent application is somewhat higher than that of the method of the invention. Here lies however, no advantage over the invention, since the

Selectivity for 1,3-butadiene in the process of

Invention is considerably higher (95.9 or 91.8 '; · ;,)

than the method of the Japanese patent application

The reason for this is that in the case of the method of the Japanese patent application a larger part of the converted η-butene to CO and

CO _{2 is converted} as a result of the combustion reaction and the conversion to the end product, namely 1,3-butadiene, is relatively low. As a result, despite the relatively high conversion of η-butadiene, the process of the Japanese palentan application is disadvantageous compared to the invention with regard to the 1,3-butadiene obtained with regard to the recycling of the unconverted material, which is customary in the industrial implementation of oxidation reactions. This is what the values do for the respective

Selectivity clear. In all cases in the method of the invention, these exceed these very substantially Comparative values that result from the known method. These values for selectivity represent that Criterion for the assessment of a large-scale technical Procedure.

Claims (2)

1 2 of the catalyst layer and the formation of unsaturated aldehydes causes the catalyst to be unsuitable, with the result that it is difficult. 1. Process for the production of conjugated to regulate the undesired consumption of used Aus-DioMnen or for the simultaneous production of 5 giugsmaterial; consequently, the conjugated diolefins and acrolein and / or the yield and selectivity of the conjugated methacrolein in question cannot be increased by catalytic conversion (a) of the gated diolefins. Furthermore, a monoolefin with a linear chain of leads to the occurrence of such undesired secondary 4 to 6 carbon atoms and 4 to 6 carbon reactions, in particular the combustion reaction, atoms per molecule or (b) a mixture of the io to a large amount of heat generation catalyst-monoolefin (a) with propylene and / or isobutylene layer with the result that an abnormal temperature with molecular oxygen in the vapor phase increase in the catalyst layer occurs locally at 300-650 ⁰ C for a contact time particularly when a Festbettreaktionsgefaß (based on from 0 ^° C. and one atm.) from 0.01 to is used, which makes it difficult to regulate the 50 seconds using a molybdenum 15 reaction temperature, and also a rapid catalyst containing bismuth oxides, because local decomposition of the catalyst area is caused by characterized in that one which the heat is generated. A way to Ver-reaction in the presence of an oxide catalysis avoiding such a drawback bietei ^ n Versatorc comprising (1) molybdenum, (2) bismuth and driving, in which the Ausgangsolefinkonzen ralion _lm (3) lithium or sodium in the atomic ratio 20 reaction gas on an extremely low value - (1): (2): (3) = (1): (0.5 to 3): (0.1 to 1) is enforced, but this is not desirable because it is too leads. a reduction in the productivity of the process 2. The method according to claim 1, characterized. draws that the catalyst on a further is the simultaneous production of Melhacro- Carrier used. * 5 lein and 1,3-butadiene from a mixture of isobutene and η-butene using a catalyst containing vanadium, molybdenum and bismuth oxides sators known. Here, however, there is a heterogeneous one Reaction instead. To the extent that conjugated diolefins are produced in the known process, this is The invention relates to a process for producing diolefins when the yields are unsatisfactory of conjugated diolefins or to keep, so that the process is practically unusable for the large-scale production of conjugated diolefins technical production of diolefins lind acrolein and / or methacrolein is through. As far as methacrocatalytic according to the known method Implementation (a) of a monoolefin with 35 lin and 1,3-butadiene can be found relative a linear chain of 4 to 6 carbon atoms takes place high temperature fluctuations and is yield «Nd 4 to 6 carbon atoms per molecule or (b) and selectivity of the desired products too low. of a mixture of monoolefin (a) with propylene It is therefore an object of the invention to provide a technical lind / or isobutylene with molecular oxygen in feasible process for the production of Kontier Vapor phase at 300 to 650 ° C during a 40 jugated diolefins or for simultaneous production Contact time (based on 0 ° C and one atm.) Of conjugated diolefins and acrolein and / or 0.01 to 50 seconds using a molyb-methacrolein using catalysts Catalyst containing danish and bismuth oxides. provide for regulating the response Catalysts for use in the oxidation is very easy and also the yield of the desired of monoolefins are known, especially for the 45 product and its selectivity even at low levels Production of butadiene from straight-chain mono temperatures are extraordinarily high. Olefins with 4 carbon atoms, ζ. B. butene-1 and The solution to this problem is according to the Butene-2. Furthermore, the oxidation of isomonoolefins is the invention that one the conversion., Ung in the opposite 5 carbon atoms, e.g. isoamylene, are known. wart of an oxidic catalyst containing (1) Mo-Here however, the yield and selectivity is 50 lybdenum, (2) bismuth and (3) lithium or sodium im of the desired product (isoprene) is very low. An atomic ratio of (1): (2): (3) - ^ (1): (0.5 to 3): (0.1 Number of catalysts for the production of up to 1) performs. Isoprene from 2-methylbutene-2 is described in Japanese The process according to the invention is generally divided into two modes of operation, Unexamined Patent Specification 25 027/1964, British Patent. If the used document 922 782 and British patent specification 915 590 55 starting olefin is a monoolefin (a), (described below. When using these, in all cases only referred to as monoolefin) (in this case both the yield i> s as well as the Selectivity of iso- the process is referred to as process I), pren can be low; they have no technical significance. the corresponding conjugated diolefin can be obtained in good condition according to Example 1 of the above booty. On the other hand, if Japanese Patent Laid-Open No. 25 027/1964 60 gangsolefin is a mixture (b) of (a) propylene and / or the reaction of 2-methylbutene-2 36.1%, which is isobutene with the monoolefin (a), (hereinafter Selectivity of isoprene (yield of isoprene also referred to as olefin mixture) (in this case based on 2-methylbutene-2 consumed) 69.3% and the process is referred to as process If), the yield only 25.0%. The most important reason why acrolein and / or methacrolein can simultaneously make these known processes as cited above 65 together with the corresponding conjugated are technically unsuitable is as follows. When the diolefin can be obtained. Oxidation reaction of monoolefins with 5 or more carbon atoms is before combustion in sators, which in the process according to the invention yer-